I've been trying to teach myself some Japanese, and there's something I've been trying to figure out--

My name is Sigmund Akira Wong. When writing in Japanese, I prefer just to go by Akira (彰). Would it be appropriate to write 王彰, using the Chinese character for Wong (aka Wa´ng) to represent my last name, or do I have to use Katakana?

I'm not sure there are hard and fast rules for this, but it seems that if you have a Japanese first name, then the Chinese character for the last name uses the Japanese on-yomi (Chinese reading). So, you'd be Oh Akira, just like Oh Sadaharu, the half-Taiwanese baseball player.

But it's a mixed bag. Historical figures are referred to by the on-yomi of their Chinese characters. In more recent times, many Korean and Chinese athletes and celebrities are referred to by their katakana-ized names.

If you're of mixed Japanese and Chinese heritage, though, I suppose you could do worse than to follow Sadaharu Oh's example...